TACHINIDAE OF AUSTRALIA 23 



pteropleuron (and sometimes much of the lower part) is bare but in a few taxa 

 (e.g. the subgen. Chrysorutilia) the hairing extends further forwards of the 

 pteropleuron than is usual. 



reclinate. Directed backwards, or upwards and backwards. 



reclinate orbital setae. One or more pairs of erect or backwardly directed setae 

 standing on the upper parts of the parafrontals (Text-fig. 3). 



The number of pairs of these setae can provide an important taxonomic 

 feature, as in Sturmiini in which genera with one pair are rather sharply 

 differentiated from genera with two or more. The setae are best differentiated 

 in the Goniinae and some Tachininae, but may be absent in males of some 

 forms though present in females (e.g. Winthemia) or may be very imprecisely 

 differentiated from the rows of frontal setae. Reclinate orbital setae are absent 

 or at least indefinite in Phasiinae and Proseninae. In genera in which males 

 have a single pair of strong isolated reclinate orbitals the females may show 

 two pairs, but have the lower pair weaker than the upper (main) pair and 

 situated closer to each other. 



recumbent. Lying down or appressed to the surface (said of hairs or setae to 

 contrast their orientation with others that stand upright) (cf. erect). 



scutellum. The large hemispherical or subtriangular lobe of the thoracic dorsum 

 behind the scutum. 



The shape and degree of flattening of the scutellum, and the nature of its 

 hairing, provide minor taxonomic characters. 



scutum. That part of the mesonotum lying posteriorly to the transverse suture 

 (Text-figs 4 & 7). 



Morphologically this is only the posterior part of a divided scutum but the 

 term remains useful in taxonomy. The scutum as such has little use in taxonomy 

 except for its patterning and pollinosity. 



second aristal segment. The more distal one of the two basal segments of the 

 arista. 



This segment varies in its length (to a greater extent than the first aristal 

 segment) and can provide a useful feature. 



second costal sector. That segment of the costa lying between the apices of veins 

 Sc and R r (Text-fig. 10). 



The presence or absence of small fine recumbent hairs along the ventral 

 surface of this costal sector provides a useful taxonomic and key character at 

 various levels in different parts of the family. The hairs when present are 

 additional to, and quite distinct from, the marginal costal setulae. Sometimes 

 whole tribes have one condition or the other (e.g. second costal sector bare below 

 in all Rutiliini or haired below in all Thelairini), but elsewhere the character 

 may be generic only (e.g. in Blondeliini) . 



seta, setula. Not differentiated from each other on any absolute criterion, but 

 seta generally reserved for any strong and obvious bristle forming a particular 

 component of the formalized chaetotaxy, and setula for a small stiffened hair. 

 Setulae are commonly serially arranged, as along the costal margin, down the 

 facial ridges or in the postocular row. 



